Because of the space confinements within an aircraft, coupling assemblies for interconnecting tubular conduit members are often located at places within the aircraft which are difficult to reach, to see and to service. Thus, it is desirable to have couplings which can be easily manipulated with one hand by the mechanic for closure and which can be visually and tactilly inspected easily to ensure that closure has in fact occurred. In addition, it is necessary that the fastening device used on the coupling have redundancy features to minimize inadvertent opening of the coupling should a latch become damaged.
The latching or locking art is well developed. There are many examples of latching devices having a central tine for guiding the latching mechanisms together and spaced outer tines which are resilient or bendable for moving them between latched and unlatched position for separating and connecting the latching members. Examples of these are U.S. Pat No. 3,181,189 to Leyden which shows a latching mechanism for connecting a toothbrush shank to an electric motor. U.S. Pat. No. 4,150,464 to Tracy; U.S. Pat. No. 4,631,787 and U.S. Pat. No. 4,639,982, both to Kasai; U.S. Pat. No. 4,662,040 to Terrell, et al.; and U.S. Pat. No. 4,712,280 to Fildan each show buckles for straps wherein one of the members has a central flexible tine spaced on either side of the central tine for receipt in a suitable receiving member. Although each of these devices is satisfactory for its intended purpose, none provides an arrangement wherein the tines are as readily accessible as is desirable in an aircraft configuration.
U.S. Pat. No. 4,534,090 to Skobel discloses a latching mechanism having a pair of tines with curved ends which reduces the surface in engagement with the receiving member which will lower the frictional forces on the device when it is being connected or released. However, it has none of the other features of the present invention.
U.S. Pat. No. 4,577,377 to Kasai and U.S. Pat. No. 4,688,337 to Dillner, et al., each disclose a female member having tapered side edges which engage the outer surfaces of the flexible tines. However, the geometry of the devices is not such that once they are released, they will tend to be urged apart by the reactive forces within the devices.
U.S. Pat. No. 4,881,760 to Runkles, et al., discloses a pair of arcuate coupling halves pivotally joined together at first adjacent ends. A central longitudinal channel is formed at the other end of one of the coupling halves with a pair of locking channels formed respectively on opposite sides of the central channel. A central tine is extendable longitudinally from the outer surface of the end of the other of the coupling halves and a pair of resilient locking tines extend respectively from the outer surface of the opposite end of the other coupling halves on opposite sides of the central tine. When closed, the resilient locking tines snap into engagement with the locking surfaces of the respective channels to releasably hold the coupling halves in closed position.
U.S. Pat. No. 4,900,070 to Runkles, et al., is similar to the previous patent but has rigid tines which are pivoted at one end and are moved from a predetermined position during closing against the force of a spring. While each of these inventions are suitable for their intended use, sometimes only one tine is completely locked. Since the coupling is often in a location where it cannot be easily viewed, the mechanic will hear or feel one tine snap into place and will believe that both tines are locked when, in fact, they are not. Thus, the redundancy feature is not effective.